1. Field of the Invention
The present invention relates generally to a chair, and more particularly to an innovative one which is designed with a pre-pressing structure.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
At present, there are various types of chairs that are functionally designed to meet ergonomic requirements for improved comfort. Since the seat cushion and back of common chairs are assembled securely, the chair back becomes a fixed part. In such a case, the users have to take a fixed sitting posture, leading to discomfort when sitting for a longer time. To overcome the aforementioned problems, a chair with an elastic structure has recently been developed, i.e.: an elastic structure is set at the assembly portion of the cushion and back of chair, so that the back of chair can be tilted back and rebounded via the elastic structure.
However, some shortcomings of the structural design of said chair with elastic structure are still observed, wherein the elastic structural design is a crucial influential factor. Elastic fatigue cannot be resisted in a conventional structural design, leading to shorter service life of the chair. Thus, it would be an advancement in the art to provide an improved device that can be advantageous to users.
Moreover, a chair with an elastic structure at the joint has been developed in prior art, as illustrated by U.S. Pat. No. 6,682,252, wherein a torsion tube is assembled at the preset joint of the chair, and then a set of bolts and nut positioning members are meshed with the tooth, so that the joint and torsion tube could be assembled together in a limited condition. Meanwhile, when the joint generates pivotal motion, the torque tube will be twisted to accumulate resetting elasticity. Yet, it is found in practical applications that owing to numerous components, the installers must consider the relationship among so many components such as: some parts corresponding to the joint, torsion tube and bolt and nut positioning members. And they may be assembled using other special toolkits. Hence, some problems and shortcomings, e.g.: difficult and time-consuming assembly and higher manufacturing cost, need to be overcome.
Thus, to overcome the aforementioned problems of the prior art, it would be an advancement if the art to provide an improved structure that can significantly improve the efficacy.
Therefore, the inventor has provided the present invention of practicability after deliberate experimentation and evaluation based on years of experience in the production, development and design of related products.